................................................................................................................................... ii Acknowledgments .................................................................................................................... v List of Tables......................................................................................................................... viii List of Illustrations ................................................................................................................... x List of Abbreviations .............................................................................................................. xii I. Literature Review ................................................................................................................ 1 Planting Date and Variety Selection on Winter Production .......................................... 1 Crop Simulation Modeling .......................................................................................... 5 References ................................................................................................................ 10 II. Effect of Planting Date and Varieties Selection on Wheat Yield and Yield Components..... 20 Abstract .................................................................................................................... 20 Introduction .............................................................................................................. 21 Materials and Methods .............................................................................................. 24 Results and Discussion .............................................................................................. 26 Conclusion ................................................................................................................ 37 References ................................................................................................................ 39